Air conditioning unit having means for providing filtered make-up air

ABSTRACT

An air conditioning unit having a housing divided into a lower compartment containing a refrigerant condenser and condenser fan and an upper compartment containing an evaporator and a conditioned air fan, is provided with a make-up air passage in the partition dividing the two compartments. An air filter pad is positioned between an air inlet opening to the second compartment and the refrigerant evaporator so that its large area face is exposed for filtering air passing to the evaporator. The make-up air passage is disposed along the bottom side of the air filter pad so that the make-up air passes from the condenser fan upwardly through the small area bottom side of the air filter pad before passing in heat exchange relation with the refrigerant evaporator. A modified embodiment is described wherein the makeup air bypasses the refrigerant condenser.

United States Patent [191 Berger AIR CONDITIONING UNIT HAVING MEANS FOR PROVIDING F ILTERED MAKE-UP AIR [75] Inventor: Isaac Berger, Hacienda Heights,

Calif.

[73] Assignee: Carrier Corporation, Syracuse, NY. [22] Filed: Dec. 6, 1971 [21] Appl. No.: 204,936

[52] US. Cl ..62/427, 62/97 [51] Int. Cl ..F25d 17/06 [58] Field of Search ..62/97, 317, 427

[56] References Cited UNITED STATES PATENTS 2,736,176 2/1956 Carlton ..62/3l7 2,822,674 2/1958 Simmonsm. ....62/3l7 3,018,642 l/l962 Lathrop ...,62/427 3,262,491 7/1966 Selhost ..62/427 Primary Examiner-Williarn J. Wye Attorney-Harry G. Martin, Jr. et a1.

[57] ABSTRACT An air conditioning unit having a housing divided into a lower compartment containing a refrigerant condenser and condenser fan and an upper compartment containing an evaporator and a conditioned air fan, is provided with a make-up air passage in the partition dividing the two compartments. An air filter pad is positioned between an air inlet opening to the second compartment and the refrigerant evaporator so that its large area face is exposed for filtering air passing to the evaporator. The make-up air passage is disposed along the bottom side of the air filter pad so that the make-up air passes from the condenser fan upwardly through the small area bottom side of the air filter pad before passing in heat exchange relation with the refrigerant evaporator. A modified embodiment is described wherein the make-up air bypasses the refrigerant condenser.

7 Claims, 3 Drawing Figures Patented May 1, 1973 FIG. 2

AIR CONDITIONING UNIT HAVING MEANS FOR PROVIDING F ILTERED MAKE-UP AIR BACKGROUND OF THE INVENTION This invention relates to air conditioning units of the type including a refrigeration system having air filtration means toremove dust and dirt from the conditioned air which is supplied to a desired location. More particularly, the invention relates to an air conditioning unit of the type described which has provisions for sup plying make-up air from the exterior of the space being conditioned to the conditioned space.

An air conditioning system may be effectively utilized to regulate the temperature and humidity in a completely closed space. to be conditioned. However, in most instances, it is desirable that some airbe supplied from an exterior location into the conditioned space to make up for losses occasioned by vent pipes or oxygen consumed by breathing and combustion. The air supplied from an exterior location to a conditioned space is customarily called make-up air. The addition of make-up air to a conditioned space is also beneficial in preventing inward drafts from the exterior which can cause cold spots in a conditioned area being heated. Make-up air is also desirable to dilute odorous contaminants which may be generated in the conditioned space, so that a portion of them may be continuously expelled from the space. Consequently, many building codes require that make-up or ventilation air be admitted into a conditioned space in quantities sufficient to prevent these undesirable effects in the conditioned space.

Air conditioning units, therefore, often provide means for admitting outside make-up air into the evaporator compartment where it is blown into the conditioned area. Where the ambient air is heavily laden with dirt, soot or other contaminants, it is highly desirable that the make-up air be filtered prior to its entrance into the conditioned space to prevent the contaminants from being objectionable to occupants of the conditioned space. Preferably, the make-up air is filtered prior to passing over the refrigerant evaporator to prevent contaminants from accumulating on the evaporator and impairing the heat transfer thereof. Often the means for providing the make-up air involves difficulty in obtaining adequate filtration without increasing the size of the air conditioning unit or employing elaborate ductwork to bring .the make-up air around in front of the air filter. This problem becomes especiallyacute when the make-up air must be taken from a side of the unit opposite from that on which the air filter is located and from which the conditioned air is drawn.

Accordingly, it is the principal object of this invention to provide a compact air conditioning unit having means for supplying filtered make-up air to a conditioned space by passing it through a side of the air filter.

SUMMARY OF THE INVENTION An air conditioning unit is provided with an exterior housing having a horizontally extending partition dividing the housing into a first compartment and a second compartment. A refrigerant condenser and a condenser fan are provided for drawing air into the first compartment through an opening therein, passing it across the condenser and discharging the air from an outlet in the first compartment. A refrigerant evaporator and a conditioned air fan are disposed in the second compartment for drawing air to be conditioned through an opening in the second compartment, passing it over the evaporator, and discharging the air from the second compartment to a location being conditioned.

An air filter pad having a large area face is located in the path of the air being conditioned in the second compartment. The pad has sufficient thickness to provide a small area side overlying the partition dividing the two compartments. A make-up air passage is provided in the partition dividing the compartments at a location such that make-up air passes from the first compartment through the make-up air passage into the small area side of the air filter pad. The make-up air, therefore, passes through the air filter pad prior to being discharged into the conditioned space. The make-up air may either pass across the condenser and be blown into the second compartment by the condenser fan or may bypass the condenser and be drawn into the second compartment by the conditioned air fan.

BRIEF DESCRIPTION OF THE DRAWINGS lower portion of an air conditioning unit in accordance with FIG. 1; and

FIG. 3 is a fragmentary cross sectional view illustrating a modification of the air conditioning unit shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT An air conditioning unit 10 is enclosed by a housing 11 having a horizontally extending partition 12 which divides the unit into a first lower compartment 13 and a second upper compartment 14. While horizontally extending partition 12 may lie in a number of planes and be shaped to suit the convenience of thedesigner, it is preferably a flat sheet of metal as illustrated in FIG. I secured to the sides of the lower portion of housing II which form lower compartment 13.

Lower compartment 13 has a refrigerant condenser heat exchanger 20 and a condenser fan 21 located therein. A condenser air inlet 23 is formed on the rear face of housing 11 and a condenser air outlet opening 24 is formed in the same face, preferably above the inlet opening. Condenser fan baffle .22 divides the first compartment into two sections. Operation of condenser fan 2! draws ambient air from the exterior of the building into first compartment 13, across the face of condenser 20 and passes it through baffle 22 from which it is discharged from the first compartment through condenser air outlet 24.

Second compartment 14 contains a refrigerant evaporator heat exchanger 30, a conditioned air fan 31 and a refrigerant compressor 36 which, together with a refrigerant expansion device 25, are connected with condenser 20 to form a refrigeration system. The second compartment is provided with a conditioned air inlet 33 in communication with a region containing air to be conditioned and a conditioned air outlet 34 is provided in the top of housing 11 for discharging conditioned air to the region to be conditioned. Preferably housing 11 is provided with an alternate conditioned air outlet 35 so that the conditioned air may be ducted either vertically from the top of housing 11 or horizontally from the same side of the housing containing air inlet 33, depending on the most convenient arrangement.

Refrigerant evaporator and compressor 36 are secured in an upright position on partition 12. Conditioned air fan 31 may be secured to an additional partition or compartment within housing 11 so that its discharge communicates with either outlet 34 or 35 depending on which outlet is to be utilized. It will be appreciated that the outlet which is not utilized will be covered after installation of the unit in the building being conditioned.

An air filter pad 40, having a relatively large area front face 41, is disposed in an upright position between air inlet opening 33 and evaporator 30 in the second compartment 14. Air filter pad is of substantial thickness so as to provide a smaller area side face 42 on the bottom of the pad which rests against partition 12. This small area face 42 lies at a right angle to the front face 41 of the filter 40 and is open so that air can pass through the small area face 42 into the filter. Operation of conditioned air fan 31 causes air to be drawn from the building being conditioned through air inlet 33 and air filter pad 40, across evaporator 30 from which the air is discharged through one of outlets 34 or 35 as desired.

In order to provide make-up air into the conditioned space from the exterior thereof, a make-up air passage 43, comprising a plurality of slots, are formed in partition 12 directly beneath air filter pad 40. Air filter pad 40 completely overlies make-up air passage 43 so that all make-up air is constrained to pass through the filter during passage to the upper compartment. Condenser fan 21 is preferably of the propeller type having a plurality of blades. Air passing across condenser 20 from inlet 23 is forced by fan 21 through make-up air passage 43. The passage of make-up air through the open lower side of filter 40 is also assisted by the action of conditioned air fan 31 which tends to draw the air from first compartment 13 into second compartment 14. Preferably make-up air passage 43 is located close- 1y adjacent the path of the radially outward periphery of the fan blades so that it directly receives the radial component of the air from the fan blades. This arrangement effectively utilizes a portion of the discharge of fan 21 which is misdirected by the fan blades, thereby making more efficient use of the fan. ln this embodiment of the invention, it will be seen that the make-up air passage 43 in partition 12 is effectively located downstream of condenser fan 21 and upstream of conditioned air fan 31 to obtain maximum make up air HOW to the conditioned space.

A sliding baffle plate 45, having slots 46 corresponding to the shape of slots 44 of make-up air passage 43 is disposed on partition 12. A plurality of screws 47 pass through screw slots 48 so that baffle may be adjusted to cover more or less of the slots forming makeup air passage 43 as desired. This enables the quantity of make-up air supplied from first compartment 13 to second compartment 14 to be regulated to comply with code requirements or other desired criteria. Screws 47 are tightened to retain baffle 45 in the desired position after adjustment.

Make-up air from the exterior of housing 11 which passes upwardly through the open small area side of air filter pad 40 is effectively filtered before passage across refrigerant evaporator 30 so that contaminants in the make-up air do not accumulate on the evaporator heat exchanger and impair its performance. Likewise the filtration of the make-up air reduces the contaminants introduced into the conditioned space from the exterior thereof.

Referring to FIG. 3 there is shown an alternate embodiment of this invention wherein an air make-up duct 50 is provided so that the make-up air bypasses refrigerant condenser 20 and passes through the side of filter 40 directly into second compartment 14. Duct 50 may be formed by a horizontal partition 51 and a vertical partition 52 co-extensive with the bottom face and the front face of the bottom portion of casing 11 which forms first compartment 13. Make-up air is drawn directly through a portion of inlet opening 23 in first compartment 13 through make-up air passage 43 and air filter pad 40 by conditioned air fan 31 without having first passed across condenser 20. In this arrangement, make-up air passage 43 is located upstream of both condenser fan 21 and conditioned air fan 31 so that conditioned air fan 31 is utilized to draw the makeup air into second compartment 14. Consequently, the make-up air bypasses refrigerant condenser 20 which avoids imposing an additional heating load on the evaporator of the refrigeration system.

The invention described with respect to the foregoing embodiments provides effective filtration of the make-up air by utilizing an open edge or side of the filter to conserve space within the air conditioning unit while, at the same time, simplifying the physical construction of the make-up air passage. An arrangement in accordance with this invention avoids the necessity of increasing the area of the large face of the air filter pad or of providing special duct work to admit the make-up air at a location where it can be filtered thereby reducing the complexity of the unit and effecting a worthwhile cost saving. The arrangement is especially well suited to air conditioning units for modular buildings where a relatively thin unit is desired.

While preferred embodiments of this invention have been described for purposes of illustration, the invention may be otherwise embodied within the scope of the following claims.

We claim:

1. An air conditioning unit comprising:

A. a housing enclosing a refrigeration system including an evaporator heat exchanger, a condenser heat exchanger, a refrigerant compressor, and a refrigerant expansion device connected to provide refrigeration, said housing having a partition dividing the housing into a first compartment and a second compartment;

B. said first compartment having said condenser heat exchanger disposed therein; an air inlet opening defined in a wall of the first compartment for admitting ambient air therein, an air outlet opening defined in a wall of the first compartment for discharging air therefrom, and fan means disposed in the first compartment for passing ambient air from said inlet opening in the first compartment over said condenser heat exchanger and discharging it through the outlet opening to condense. refrigerant in the condenser heat exchanger;

C. said second compartment having said evaporator.

heat exchanger disposed therein, an air inlet open ing defined in a wall of the second compartment for admitting air from a spaceto beconditioned into said second compartment, an air outlet opening defined in a wall of the second compartment for discharging air conditioned in the second compartment to the space to be conditioned, and fan means for passing air to be conditioned from the inlet opening in the second compartment over the evaporator heat exchanger, in heat exchange relation with evaporating refrigerant to cool the air, and discharging it from the second compartment through the outlet opening therein;

D. an air filter pad disposed in said second compartment, said air filter pad having a large area face disposed in overlying relationwith one of. said openings in said second compartment, said .air filter pad having substantial thickness forming a relatively smaller area side disposed at an angle with said large area face thereof, the small area side of said air filter pad overlying a portionof said partition between the first and second compart ments;

E. a make-up air passage defined in said partition means for passing make-up air from the first compartment to the second compartment, said make-.

up air passage comprising an opening in said partition, the side of said air filter pad in the second compartment completely overlying said make-up air passage in the partition so that all of the makeup air passing from the first compartment to the second compartment is constrained to pass through the side of the air filter pad and is filtered thereby.

2. An air conditioning unit as defined in claim 1 wherein said fan means in the first compartment comprises a propeller fan and said make-up air passage comprises an opening in said partition located adjacent the path of the tip of the propeller fan blades to receive the radial component of air discharged from the fan.

3. An air conditioning unit as defined in claim 1 wherein said air filter pad is disposed between the inlet opening in said second compartment and the evaporator heat exchanger, whereby the filtered make-up air is conditioned by passage over the evaporator heat exchanger in the second compartment prior to being discharged into the space to be conditioned.

4. An air conditioning unit as defined in claim 1 including adjustable means for covering a desired portion of said make-up air passage to regulate the quantity of makeup air supplied from the first compartment to the second compartment.

5. An air conditioning unit as defined in claim I wherein said make-up air passage is disposed downstream of the condenser fan in said first compartment and upstream of the conditioned air fan in the second compartment so that the condenser fan forces make-up air through the air filter pad into the second compartment.

6. An air conditioning system as defined in claim 1 including a make-up airduct extending from the air inlet openingin the first compartment to the make-up airpassage in said partition means, so that the make-up air bypasses the refrigerant condenser and is drawn by the conditioned air fan from the air inlet opening in the first compartment through said makeup air duct and passes through the make-up air passage in the partition and the air filter pad to said second compartment, and the filtered make-up air passes across said refrigerant evaporator before being discharged from saidunit to the space to be conditioned.

7. An air conditioning unit comprising:

A. a housing enclosing a refrigeration system including an evaporator heat exchanger, a condenser heat exchanger, a refrigerant compressor, and a refrigerant expansion device connected to provide refrigeration, said housing having a horizontally extending partition dividing the housing into a lower compartment and an upper compartment;

B. said lower compartment having said condenser heat exchanger disposed therein; an air inlet opening defined in one wall of the lower compartment for admitting ambient air therein, an air outlet opening also defined in said one wall of the lower compartment for discharging air therefrom, and condenser fan means disposed in the lower compartment for passing ambient air from said inlet openingin the lower compartment over said condenser heat exchanger and discharging it through the outlet opening to condense refrigerant in the condenser heat exchanger;

C. said upper compartment having said evaporator heat exchanger disposed therein, an air inlet opening defined in a wall of said upper compartment for admitting air from a space to be conditioned into the upper compartment, an air outlet opening defined in a wall of the upper compartment for discharging air conditionedin the upper compartment to the space to be conditioned, and evaporator fan means for passing air to be conditioned from the inletopening in the upper compartment over the evaporator heat exchanger, in heat exchange relation with evaporating refrigerant to coolthe air, and discharging it from the upper compartment through the outlet opening therein;

D. an air filter pad having a large area face disposed in overlying relation with said air inlet opening in said upper compartment, said air filter pad being disposed in said upper compartment between said air inlet opening and said evaporator heat exchanger so as to filter air passing through said air inlet opening prior topassage thereof across said evaporator heat exchanger, said air filter pad having substantial thickness forming a relatively smaller area side disposed at substantially a right angle with said large area face thereof, the small area side of said air filter pad overlying and resting against a portion of said partition between the upper and lower compartments;

E. amake-up air passage defined in said partition means for passing make-up air from the lower compartment to the upper compartment, said make-up air passage comprising a relatively small area opening in said partition, the side of said air' filter pad in the upper compartment completely overlying said make-up air passage in the partition so that all of the make-up air passing from the lower compartment to the upper compartment is constrained to pass through the side of the air filter pad and the filtered make-up air is then conditioned by being passed over the evaporator heat exchanger prior to being discharged from the air conditioning unit. 

1. An air conditioning unit comprising: A. a housing enclosing a refrigeration system including an evaporator heat exchanger, a condenser heat exchanger, a refrigerant compressor, and a refrigerant expansion device connected to provide refrigeration, said housing having a partition dividing the housing into a first compartment and a second compartment; B. said first compartment having said condenser heat exchanger disposed therein; an air inlet opening defined in a wall of the first compartment for admitting ambient air therein, an air outlet opening defined in a wall of the first compartment for discharging air therefrom, and fan means disposed in the first compartment for passing ambient air from said inlet opening in the first compartment over said condenser heat exchanger and discharging it through the outlet opening to condense refrigerant in the condenser heat exchanger; C. said second compartment having said evaporator heat exchanger disposed therein, an air inlet opening defined in a wall of the second compartment for admitting air from a space to be conditioned into said second compartment, an air outlet opening defined in a wall of the second compartment for discharging air conditioned in the second compartment to the space to be conditioned, and fan means for passing air to be conditioned from the inlet opening in the second compartment over the evaporator heat exchanger, in heat exchange relation with evaporating refrigerant to cool the air, and discharging it from the second compartment through the outlet opening therein; D. an air filter pad disposed in said second compartment, said air filter pad having a large area face disposed in overlying relation with one of said openings in said second compartment, said air filter pad having substantial thickness forming a relatively smaller area side disposed at an angle with said large area face thereof, the small area side of said air filter pad overlying a portion of said partition between the first and second compartments; E. a make-up air passage defined in said partition means for passing make-up air from the first compartment to the second compartment, said make-up air passage comprising an opening in said partition, the side of said air filter pad in the second compartment completely overlying said make-up air passAge in the partition so that all of the make-up air passing from the first compartment to the second compartment is constrained to pass through the side of the air filter pad and is filtered thereby.
 2. An air conditioning unit as defined in claim 1 wherein said fan means in the first compartment comprises a propeller fan and said make-up air passage comprises an opening in said partition located adjacent the path of the tip of the propeller fan blades to receive the radial component of air discharged from the fan.
 3. An air conditioning unit as defined in claim 1 wherein said air filter pad is disposed between the inlet opening in said second compartment and the evaporator heat exchanger, whereby the filtered make-up air is conditioned by passage over the evaporator heat exchanger in the second compartment prior to being discharged into the space to be conditioned.
 4. An air conditioning unit as defined in claim 1 including adjustable means for covering a desired portion of said make-up air passage to regulate the quantity of make-up air supplied from the first compartment to the second compartment.
 5. An air conditioning unit as defined in claim 1 wherein said make-up air passage is disposed downstream of the condenser fan in said first compartment and upstream of the conditioned air fan in the second compartment so that the condenser fan forces make-up air through the air filter pad into the second compartment.
 6. An air conditioning system as defined in claim 1 including a make-up air duct extending from the air inlet opening in the first compartment to the make-up air passage in said partition means, so that the make-up air bypasses the refrigerant condenser and is drawn by the conditioned air fan from the air inlet opening in the first compartment through said make-up air duct and passes through the make-up air passage in the partition and the air filter pad to said second compartment, and the filtered make-up air passes across said refrigerant evaporator before being discharged from said unit to the space to be conditioned.
 7. An air conditioning unit comprising: A. a housing enclosing a refrigeration system including an evaporator heat exchanger, a condenser heat exchanger, a refrigerant compressor, and a refrigerant expansion device connected to provide refrigeration, said housing having a horizontally extending partition dividing the housing into a lower compartment and an upper compartment; B. said lower compartment having said condenser heat exchanger disposed therein; an air inlet opening defined in one wall of the lower compartment for admitting ambient air therein, an air outlet opening also defined in said one wall of the lower compartment for discharging air therefrom, and condenser fan means disposed in the lower compartment for passing ambient air from said inlet opening in the lower compartment over said condenser heat exchanger and discharging it through the outlet opening to condense refrigerant in the condenser heat exchanger; C. said upper compartment having said evaporator heat exchanger disposed therein, an air inlet opening defined in a wall of said upper compartment for admitting air from a space to be conditioned into the upper compartment, an air outlet opening defined in a wall of the upper compartment for discharging air conditioned in the upper compartment to the space to be conditioned, and evaporator fan means for passing air to be conditioned from the inlet opening in the upper compartment over the evaporator heat exchanger, in heat exchange relation with evaporating refrigerant to cool the air, and discharging it from the upper compartment through the outlet opening therein; D. an air filter pad having a large area face disposed in overlying relation with said air inlet opening in said upper compartment, said air filter pad being disposed in said upper compartment between said air inlet opening and said evaporator heat exchanger so as to filter air passing through said air inlet opening prior to passAge thereof across said evaporator heat exchanger, said air filter pad having substantial thickness forming a relatively smaller area side disposed at substantially a right angle with said large area face thereof, the small area side of said air filter pad overlying and resting against a portion of said partition between the upper and lower compartments; E. a make-up air passage defined in said partition means for passing make-up air from the lower compartment to the upper compartment, said make-up air passage comprising a relatively small area opening in said partition, the side of said air filter pad in the upper compartment completely overlying said make-up air passage in the partition so that all of the make-up air passing from the lower compartment to the upper compartment is constrained to pass through the side of the air filter pad and the filtered make-up air is then conditioned by being passed over the evaporator heat exchanger prior to being discharged from the air conditioning unit. 